Plant Nucleases. II. Properties of Corn Ribonucleases I and II and Corn Nuclease I

摘要

A classification system is presented to distinguish 3 corn nucleases—Ribonuclease I, Ribonuclease II, and Nuclease I—which were described in the first paper of this series. The 2 ribonucleases are specific for RNA, are endonucleases, and liberate purine and pyrimidine cyclic nucleotides from dinucleotide monophosphates as well as from RNA. Ribonuclease I and II hydrolyze the purine cyclic nucleotides to 3′-nucleotides, while Ribonuclease II may also act on the pyrimidine cyclic nucleotides. Ribonuclease II is best characterized by its molecular weight of 17,000, by a higher pH optimum than Ribonuclease I, and by its absorption onto microsomes.